Do Noise Traders "Create Their Own Space?"
分析金融市场的近视交易者模型，发现经典均衡存在，而噪声均衡仅在强假设下唯一存在，且近视并非噪声价格的必要条件或充分条件，对投资和监管政策推导困难。
We analyze myopic trader models of noisy prices in financial markets. Unlike extant analysis, such as De Long et al. (1990a), a classical equilibrium exists in our analysis, e.g., a riskless perpetuity is priced by arbitrage and its price does not vary with noise. A unique noisy equilibrium exists only when i) noise traders' beliefs are rational regarding volatility and irrational regarding expected returns, and ii) noise traders can hold infinite positions. In the absence of these strong assumptions, multiple noisy equilibria can coexist with the classical equilibrium, but these equilibria exhibit conflicting comparative statics. Furthermore, the price of a long-lived asset with risky cash flows can vary with noise even when investors are not myopic. One conclusion is that myopia is neither a necessary nor a sufficient condition for noisy prices. A second is that it is difficult, if not impossible, to use myopic trader models to derive implications for investment or regulatory policy.